Positive printing in color photography



Patented Dec. 16, 1941 I POSITIVE PRINTING IN COLOR PHOTOGBAPHY EdwinBower Bessel, Canoga Park, Calif.

No Drawing. Application April 8, 1939, Serial No. 266,781

26 Claims.

This invention relates to the art of color photography, and moreparticularly to a. newand improved process for producing composite colorprints combining light-reflectant and light-transmittantcharacteristics, thus being equally valuable when-viewed in the ordinarymanner, .by

reflected light as a flprlnt or when illuminated I from behind, as atranslucency.

The chief characteristic of this composite color print is its markedsimilarity to the product designated generally in the photographic tradeas a paper print in natural color, yet the type of print disclosedherein is definitely paperless, having no dependence whatever on paperas a light reflectant medium.

Thus, a main object of the invention is to provide a print valuableeither as a translucency, or viewable by reflected light.

An object is to provide a composite color print which readily lies flat,because each superposed element thereof is of related material, ofidentical tensional factor, which is therefore unafof composite printmaking useful in aerial military photography by means of its great speedin manuiacture, together with lightness of weight, and flexibility ofthe finished print which permits it to be rolled.

Another object is to provide composite color prints which may beattached, in standard photographic manner by means of dry mountingtissue, to a plane surface mounting, retaining the flatness which isessential to lasting value in a color print.

Another object is to provide for advertising usage composite colorprints suitable for window displays and viewing. by daylight, which atnight may be viewed as a translucency by transmitted light, without thedegradation of color value and display of paper grain which would beobjectionable in similarly viewing a composite color print which waspaper containing.

A still further object is toprovide, tising usage, a composite colorprint including advertising matter such as a photographic reproductionof a drawing, or lettering, in combi-. nation with a natural colorphotograph, which,

when viewed from the front, by reflected light, shows only theadvertising display but which, when lighted from behind shows bytransmitted for adverlight a pictorial display comprising the naturalcolor photograph produced by a build-up of supprposed registeringimages.

Also another object is to provide for the graphic arts of photoengravingand lithography a composite color print particularly suited forreproduction, by means of its adaptability to copying byeither reflectedor transmitted light, but particularly so that it ispossible, at theoption of the engraver, to make one or more of his color separationnegatives, in copying'the composite color print for reproductionpurposes, by transmitted light, as a translucency, and to make one ormore of his separation negatives, in varying selective sensitivities orfiltrations, by reflected light, thus, for instance, enabling the makingof a key-print separation, for printing in the graphic artsin gray, tobe made from the composite print as a translucency, thus being lessharsh and contrasty than the same composite print copied as a reflectedlight print. To a skillful engravensuch possibility of variation ofcontrast oiiers valuable possibilities of color control, particularly inlithography, when as many assill color separations are made from asubject, for as many printings in difierently colored inks.

Still another object is to provide a dual pictured print, usefulfor-advertising purposes, in which the finished product consists of twoseparate build-ups; the front build-up, on transparent image-bearingmultiple cellulosic films in permanent adhesion and registerbeingseparated from the rear build-up by means of semiopaque cellulosic filmmaterial so that, when viewed by reflected light, only the front builduppicture is visible, but when illuminated from behind, both'of thepictures, from the front and rear pictorial build-ups, are viewed as acom-,v

- bination picture, permitting the production of vision type of picturesparticularly valuable in the field of advertising.

Other objects, advantages and features of the invention-may appear fromthe following subjoined detail description thereof, and the appendedclaims (no drawing being necessary to illustrate the'invention, none isfurnished).

In accordance with this invention it has been found that new andimproved results can be obtained by associating in a print composed of abuild-up of transparent image-bearing fllms of only the type of materialof which the imagebearing films are composed, omitting all materials oialien characteristics, such as paper, from the permanently adhesiveassociated supersition, and substituting therefor an opaque material ofthe same composition.

Thus,in a build-up print in which the imagebearing films arecellulosic,'the reflecting element, according to this inventiomshouldalso be cellulosic and opaque.

Similarly, in a build-up print of image-bearing celluloidal films ofnon-extensible nature, the reflecting element should preferably beanother celluloidal opaque film.

However, it is not foreign to this invention to employ for a reflectiveelement, with a celluloidal I or celloidal build-up a cellulosic opaquereflecting material of similar expanding and contracting tendencies inrelation to humidity conditions.

In accordance with this invention, however, a paper refiectant surfaceis never employed, the omission of paper being a paramount feature ofthe process.

It is well knownin the art that superposing of transparent image-bearingfilms in color which are so printed as to correctly reproduce inpositive form the selective sensitivity recordings of sensations in aset of color separation negativeswill, when viewed by transmitted light,produce a transparency. As an instance, the trade-marked productfchromatone, consisting of collodion films temporarily attached to apaper base, which is removable in the processes of developing, fixingand washing, is capable of being printed, in a photographic mannerbehind three negatives of a standard color separation series, afterwhich the collodion film positives resulting from exposure behind thethree negatives are appropriately colored in yellow, magenta and blue,representing, in the order named, the printings from the blue sensation,the green sensation and the red sensation recording negatives. The threecolored positives, so produced, might thus readily be joined together inadhesion to form a transparency, However, the three collodion,colored-up image-bearing films are in themselves without great valuebecause in-- sufllciently rigid to handle, and insufiiciently lightrefiectant to act as a positive print for viewing by reflected light. ithas therefore been customary, and recommended by the manuiacturers ofproduct, to the three collodion films in superposed registry upon whitepaper, to act as a refiectant element. However, there has been. a greatdrawback and disadvanto prints so produced, inasmuch. as the compositepaper coilodion print has a marked tendency to wrinkle, curl and buckle,clue to the tensional difierences between the buildup of films ofcoilodion nature and that oi the paper used as light refiectant element.

It is equally well known in the art that cellulosic films, such as theregenerated cellulose manufactured by Du. Font and their patentlicensees and universally sold under he tradenarne Cellophane have thecapacity of imagebearing by means of chemical toning, such as irontoning for blue, and bichrornate-dye image production in a wide range ofcolors. Such image-bearing may be designated as of the integral type,inasmuch as the coloration runs entirely through the depth oi thecellulosic film, in contradistinction to the surface image-bearing whichmay be attained by the affixing of a carbon tissue image to a Cellophanesheet, as a support, in the manner taught by Spencer, in his Britishpatents. In a manner equivalent to the production on Chromatonecollodion stripping film, images in three colors may be produced onCellophane" films as carbon tissue surface images, as chemically tonedimages or as bichromate-dye images. It is possible to combine, in onecellulosic build-up, image-bearing colored films produced by more thanone, or by all of these methods: for the yellow, an acid-dye bichromateimage might be produced from the i aeeascv blue sensation negative of acolor separation series; for the blue, a chemical iron tone image mightbe produced from the red sensation negative; for the magenta, printedfrom the green sensation negative, a surface carbon tissue imagebearingcellulosic film might be utilized, whether one, or multiple types ofcellulosic bearing images producedby such methods are used in combination, is a matter of taste as far as the photographic worker isconcerned, because, whatever the production method used, the factor ofregi tration of the images will be found identical, inasmuch as it iscommon property and knowledge in the trade that Cellophane, stretchedwhile wet and expanded, in a normal manner and with out undue pressureon a non-extensible support, such as water pervious metal, glass, enamelor Bakelite, may be dried, an image caused therein to form, be againimmersed, and have the power of retaining identity of image proportionto other images similarly formed in other films of the identical type ofmanufacture, even if used to hear an image in color of another type, anexample being the association in registry of integral" image-bearerswith surface image bearing films.

As an improvementover these known methods, I disclose new methods ofpreparing Cellophane films for color printing, which consist of thefollowing operations, for. example I produce a film sensitive to light,and resulting in blue coloration by the properly timed exposure behind anegative in the following manner: A cyanotype blue solution, containingiron and ammonium citrate, potassium ferricyanide and hydrochloric acid,is placed in a glass dish. Cellophane films, cut to a-desired size, areimmersed therein, a number may be placed in a dish, agit tion isdiserable. The Cellophane can absorb only a definite fiuid content,sufficient time is allowed in the dish for such maximum absorption totake place, then one individual is taken from the dish, placed on aplane, smooth, non-absorptive surface, such as glass, and the surplussensitizer removed from the celiulosic film by squeegeeing. The film maybe left in adhesion to the glass, until dry, then exposed to lightbehind a negative, washed in water, a blue print on Cellophane film,suitable for the blue member in'a three color build-up resulting. When,instead or" a chemical blue toner, an acid dye solution is used, themethod is the same, except, after soueegeeing to remove surplus dye, thefilm is subjected to another bath, in a bichromate, following which itis again squeegeed, to remove surplus bichromate, and dried in the dark.It has been found desirable to immerse the glass plate with the adherentdyed, squeegeed film, directly in the bichromate solution, which may,alternately, be applied manually, or by vaporization. Obviously, suchtreatment may be accorded to the dyed film, whether completely dried, ordamp from the first process of dye im- 'pregnation.

tive from which it was exposed to light, allowing' a few minutes for dyeabsorption. Simple acidified washing removes the surplus dye from partsnot affected by the photographic exposure to light, an excellentimage-bearing Cellophane film, of great contrast, resulting. Instead ofimmersional applications of either the bichromate solution, the dyesolution, or both, manual or mechanical application may be substituted.

In the known photographic art, to convert .a build-up of image-bearingsheets of whatever nature as to composition, but transparent, into alight refiectant print, viewable as an ordinary painted or printedpicture might be viewed, it has been necessary to use a paper base ofsome kind, and to build up, on this paper base, and in adhesion, theconstituent color-images, in the material selected, to form a naturalcolor picture. This building up process is used in "carbro or carbontissue prints built up directly upon a sheet of paper with extremelythin, unsupported carbon tissue films; by Cello-' phane supported carbontissue images, by-dye or toned Cellophane image-bearing films; bycollodion films of the Chromatone" or "Kodalith stripping film type. Itis to be noted that the extremely thin, non-tensional carbon-tissueimages of the "carbro type offer no special trouble in wrinkling orcurling after the print has been manufactured, but that all types ofcollodion films, Cellophane films or celluloidal.

films, bearing images, possess such radically different factors ofstress and tension from the 3 maybe readily mounted with suchdry-mounting tissue methods: such printaoi type known in the art,include Carbro prints and Eastman wash-off prints," which are relativelythin. On the other hand, it has been almost impossible to satisfactorilymount on cardboard or other .plane surface, by means of dry-mountingtis-v paper, with its perpetual tendency to curl. Such heavy prints havein general necessitated double mounting, or taping upon heavy,board-like material for permanent support, adding to exhibition, mailingand framing difficulties. However, in the case of flexible build-upprints of cellulosic films, I have discoveredthe. marked advantage ofbeing able to use dry mounting tissue methods in a manner similar toprints paper on which they are mounted for light re- 1 fiectantpurposes, while wet and in process of ages, that, in drying, tendenciesto wrinkle, curl, buckle, blister and crack are almost certain to benoticeable, even in such instances as when cellulosic sheets are causedto adhere to the back of the paper light-refiectant member of thebuild-up, in an effort to neutralize the tension caused by theimage-bearing material on the front of the paper sheet. Changes ofweather and humidity, over a period of time, often result, by means ofsuch wrinkling, in destruction of the exhibition value of such prints,and this tendency, known in the art, has always proved detrimental tothe commercial usage of such paper-combining prints, in which theadhesive association with transparent cellulosic, colloidal orcelluloidal films has so generally resultedin wrinkling and curlingtroubles.

A marked disadvantage and detriment to cellulosic prints of the build-uptype, combining image bearing Cellophane films in supersit on on paperwith other Cellophane" films on the back of said paper as a means tominimize curling tendencies, has been the thickness and bulk of theresulting print, ofiering serious difiiculties in mounting. In thephotographic business of supplying prints for use in commerce, thatis,-in the commercial advertising usages, as well as portraits, the mostacceptable method for mounting a print, and that in general usage inpreparing prints for exhibition, has been with materials such as the"dry mounting tissue? sold under that trade name by the Eastman KodakCompany of Rochester, New York. By this means, a print may be afllxed toa papercardboard plane surface mounting, by means of heat applicationwhich so melts the dry-mounting tissue that it becomes permanentlyadheof carbro or wash off, type. Unlike the paper containing prints, in.which the paper and the cellulosic films haveatendency to separate ifthe print is cut into the paper portion,

in trimming, the all-cellulosic build up may-be trimmed, aftercompletion, to any desired size on a photographic trimming cutter, andthen' dry-mounted.

Oneof the most important commercial markets possible for natural colorphotography-is in window display use; heretofore thedifilculty andexpense of manufacturing color prints has made the cost for such usagealmost prohibitive. By my methods herein disclosed, it will be possibleto produce color prints at much less cost and trouble than heretofore,due to the simplicity of the process and the obviation ofloss which hasalways occurred heretofore in print making owing to the percentage ofprints made which become valueless due "to wrinkles, buckling, blistersand kindred evils caused by the adhesive association of paper and theunrelated, differing tension factor materials comprising andsuperimposed build-up of image-bearing. transparent films.

When, according to this method, the light re- .fiectant quality in thecomposite built-up color tained by lighting the printfrom behind, and.

thus viewed by transmitted light, as a trans-, lucency, the same printthat proved beautiful and effective as a daylight display becomes evenmore attention-arresting at night. For theatrical and motion picturedisplay frames the commercial value of such a print is obvious.

Another great drawback, known in the art in I connection with theprocess of building up transparent films to form composite color pictureon a light refiectant paper base has been overcome by my novel method ofproduction. Paper by its very nature has the tendency to absorb and 1hold water to much greater degree than cellulosic film of theCellophane" type.

Because of this water absorbing and holding nature of paper,particularly in the water its removal from the glass support, in wet,

weather, a reverse action. takes place, and. oftenwhen a composite colorprint is seemingly dry and removed from its giass'manufacturing support,the paper light reflectant element therein is actually still'damp, withthe result that it soon begins to curl and wrinkle.

Experiments with 'the .type of all-cellulosic print herein disclosedhave proved conclusively that the composite thus formed dries veryquickly and evenly, thatconsiderable heat and forced air may be used indrying, without detriment to the print, thus making possible andpractical the removal of the finished composite color print.

from its manufacturing support in as little as thirty minutes aftercompletion of the build-up, definitely overcoming a most hazardous anduncertain factor always present in the making of paper containingbuild-up prints. Such speed of completion is an added value'in thedelivery of finished work, and in military aerial usage fills therequirements much more fully than any type of print requiring aconsiderable period of time to dry. The flexibility of these compositeprints permits military usages impossible in a completely rigid, papercontaining build-up prin In a preferred form of this invention, a rigidsupport is chosen which in size is larger than the print to be made. Asan illustration, the making of an 11 by 14 inch print will be described.

The rigid, non-extensible support may be of glass, Bakelite, metal orCelluloid. It need not be transparent, but must not be water pervious.

I For the making of an 11 by 14 inch print it should be 12 by 15 inchesin size.

Regenerated cellulose of white opaque characteristics, such as Du PontCellophane #300 plain opaque is cut to 14 by 18 inch size, thus beingmarginally larger than the rigid support. A sheet of this opaquematerial is placed for a few moments in a pan of water, then placed overthe rigid support, so that the overlapping margins drop down, it beingadvisable that the rigid support be elevated above the working table,for instance, on an eight inch block of wood. The overlapping edges aremade to adhere to the back of the support by a convenient adhesive,after the surplus water on the surface of the cellulosic material incontact with the support is removed by pressure, preferably by awindowwashing type of squeegee. Note that only the overlapping edges arecaused to adhere to support, and only to the back of the support.Another sheet of the same opaque cellulosic material is now put into thepan of water, the operation is repeated; only the back of, the supportis brought into adhesion with the overlapping marginal material ofopaque Cellophane. The third sheet ofidentical material is put in thepanof water: this time the entire surface of the second sheet of opaquematerial is lightly but evenly covered with the adhesive material, whichmay be a solution of transparent, waterwhite gelatine. The marginal,overlapping edges are turned under, and caused to adhere to the back ofthe support. If it is desired that the finished print shall be fairlyheavy, and used 'mainly for viewing with reflected light, a fourth sheetof opaque cellulosic material is added in a manner identical to theoperations governing the third sheet set'down.

It should be noted that no adhesive is placed between the first andsecond sheet put down, the object being to protect the print from anypossibility of seepage of adhesive material that might reach the surfaceof-the rigid support,

making it diiilcult to later remove, without tearing the cellulosicunder surface, from the rigid support. After removal of the finishedprint, in a manner which will be described, this first sheet 'put downis peeledoif and thrown away. Howused. If two sheets of opaque materialcorre- I picture.

spending in weight to standard #600 transparent Cellophane were used,they should, in adhesion, provide adequate opaquity for lightreflection, though another might optionally be added, if fi rtherstiflening of the finished print was desira le.

The opaquecellulosic backing is now ready for the superposing inregister of transparent image bearing films comprising the compositecolor By whatever method the image-bearing sheets are produced, the nextstep is to select one of the component colorations, ailix perma- 'nentlyby means of adhesive the transparent material bearing it, on top of thefinal opaque sheet adhering in supersition to at least one other opaquesheet marginally adhering to the back of the rigid support, see thatthis image-bearing sheet is properly in adhesion, without air bubbles,and then, on top of -it, in whatever sequential order of colorations isdeemed advisible affix in register and adhesion the remainingimagebearing transparent sheets needed to complete a natural color stillpicture. The composite picture may now be dried by means of an electricfan, in a few minutes.

After the drying operation is complete, a sharp knife edge is used tocut through all the superposed layers of material on the front of therigid support, comprising both the transparent imagebearing sheets andthe opaque reflectant sheets, right through to the support. This cuttingshould be outside the pictorial area of the imagebearing sheets, in themargins on the front of the support. After this cutting, the composite,complete print readily peels off from the support, and can then betrimmed to desired size and proportion and mounted, at once, with drymounting tissue, or put between rigid, smooth plane surfaces for futureusage. Such prints may obviously be used unmounted.

The image-bearing transparent sheets may be considerably smaller thanthe size, of the rigid support. If a matte surface is desired, theentire composite print may be covered with a cellulosic, matte surfacetransparent material such as marketed under the trade name ofTransolene," or a product of similar nature, such as a matte surfacedwater absorbent cellulosic sheet manusource isprovided behind thecomposite picture tone collodion stripping paper: in each case, afterprinting development and fixation, the

silver image is colored byknown methods of toning or dyeing, and thenassembled in -regis-,

the lettering and picture are both visible.

The same principle may be utilized by laying down, over a single opaquesheet on the rigid support, the series of transparent image-bearingsheets in registered superposed adhesion necessary to complete a naturalcolor picture. For

, instance, this might be the pictureof a lovely tered adhesion on theopaque cellulosic material comprising the refiectant backing of thisinvention. Carbon tissue prints on thin transparent supports, cellulosicor celluloidic, are also suitable for employment in association with thetype of opaque backing disclosed herein.

We have sometimes found it more convenient, in practice, instead ofoverlapping the white opaque Cellophane films comprising the lightreflectant-light translucent backing, over the rigid support, asheretofore described, to use a larger sheet of glass than 12 by 15inches, as previously suggested for an 11 by '14 inch print. Take, forexample, a piece of glass 15 by inches in size; cut the opaque whiteCellophane sheet to 14 by 18 inches Then, instead of the marginaloverlapping previously suggested, put

the wet sheet on the glass, squeegee out the surplus water, with a brushplace the adhesive only on the outer edge of the Cellophane. Upon thissheet, in supersition, additional sheets of the white opaque cellulosematerial are added, these sheets beingmade adhesive to each other. andthe first sheet by all over adhesive applications. When the requirednumber of sheets are in place for the opaque or translucent backing, theimage bearing sheets are put down .in succession; first, for instance,the yellow positive image bearing Cellophane, second, the magentapositive image bearing Cellophane in exact registry, then the blue imagebearing Cellophane film, and if a four color print is desired, a blackimage transparent film is added, all in registry and in permanentadhesive relationship to the opaque backing films. All these operationsare carried out, as to registration, while the image-bearing films arewet; when the build-up is complete, the composite color photographshould be quickly dried and removed from the temporary support bycutting with a sharp knife between the pictorial edge of the picture andthe margin of the lower Cellophane sheet attached to theouter edge ofthe rigid support.

In the manufacture of window display color pictures by this method, inwhich the requirement is viewability by either transmitted or reflectedlight, the number of opaque sheets behind the image-bearing sheets iskept at a minimum.

The method of manufacturing a color picture which is not at all visibleby reflected light, but which may be viewed as a translucency when alight source is provided behind it, may be as follows: The opaquebacking is made in the usual manner; the image bearing sheets aresuperposed in registered adhesion, further opaque sheets, or a singleopaque sheet, is caused to adhere over the composite color picture. Onthis sheeting of opaque material, for advertising pur-' poses, alettering may be printed in known manner.- The underlying pictorialcomposition is not now apparent to a casual glance, but such lettering-as is provided on the surface of the final opaque sheet is readable.When a light house, with children playing in the yard. Then an opaquesheet, or multiple opaque sheets, are arranged in adhesive supersitionover this complete picture; With image-bearing transparent sheets ofanother subject (which for 11- lustration might be a young couple seatedon a hilltop, with a clear sky above them), further build-up ofsuperposed ,registering adhesive sheets completes another color picture,visible,

of course, by reflected light, while the rear picture remains invisiblebehind the opaque sheet. When transmitted light source is providedbehind the picture as a whole, the lovely house, with children playingin the yard, is shown as the young couples vision, in the sky. Suchcombinations of dual ideas are obviously valuable from an advertisingstandpoint.

Speed of completion of any type of color print is a most importantfactor in determining its commercial value. It should be noted that theordinary build-up print consisting of several colored image-bearingfilms, mounted on top of a light reflectant paper sheet, is turned backby other multiple adhesively attached cellulosic films in the usualeffort to minimize stress or tension and thus reduce the curlingcharacteristics of such a composite print, requires after the completionof the image-bearing film build-up a period of from six to twenty-fourhours, depending on humidity and temperature conditions, before it issufliciently dry to be removed from its temporary rigid support.

I have demonstrated that a print produced by my new and unique method ofassembling multiple, transparent image-bearing films in permanentadhesion with each other and multiple imageless white opaque cellulosicfilms results in a composite color picture. which may be dried veryquickly and removed from its temporary rigid support. No detrimentaleffect on. the composite color print is caused by the use of warm,

forced air, and by the combination of heated air.

and an electric 'fan'we have discovered that it is possible to removesuch a print from its support, fully dried and ready for any commercialusage, including dry mounting, in as short a time as twenty minutesafter the image-bearing sup'erposing build-up operation is complete. Intime of war, the quick completion of military color prints would be ofextraordinary value to the. aerial forces of our nation, the ability toassemble such image-bearing color films in a flying laboratory," anddrying them speedily by readily available air pressure being a featureof obvious importance.

Within the proper scope of this invention are several other variationsof composite color print making, in which all the factors of stress andtension are equalized by employing similar material for each associatepermanently adhesive film in a composite build-up.

For instance, commercial usage can be found occasionally for such acomposite build-up which is entirely of light transmittant and not lightreflective characteristics, but which is sufficiently rigid forhandling, trimming with a cutter and standing upright in the manner ofan ordinary photographic print, let us say on a mantlepiece restingagainst a wall; Such a print is produced, by my method, by the meresubstitution of multiple transparent cellulosic sheets on the backing,instead of multiple semi-opaque sheets. I have discovered that a rigidtransparency, so

produced, may be readily converted into a light-- refiectant printeither by adding another or multiple sheets of semi-opaque film at anylater time, by adhesion, or by spraying on the back thereof an evencoating of white opaque cellulosic material in solution, or other whiteopaque material that may be readily applied with an air brush.Kodachrome transparencies, in themselves consisting of multipleemulsions differentially colored to produce a composite color photographadherent to a celluloidal base, may be rendered light-reflectant andutilized as translucencles when adhesively mounted upon a base ofsemi-opaque cellulosic material or when treated, with a spray, on theback celluloidal side, to obtain a light refiectant effect. Similartreatment may convert either Dufaycolor transparencies or Agfacolortransparencies into translucent light reflecting prints. It is obvioustha' such conversion to translucency increases the value of such.transparencies, the combination of multiple color registered images inany form to complete a composite color photograph with a paperless,light-refiectant yet translucent support being fully within the scope ofthis invention, whether such a translucent support be used as a basebefore or after the coloration of the images or as separate from, or asintegral with such images in the process of coloration or processing.

Having thus described the invention, what I claim as new and novel anddesire to secure by Letters Patent oi the United States is:

l. in the art of color photography, the method of producing a compositecolor photograph which comprises providing in appropriate colorationmultiple transparent image-bearing films representing in positive formthe selective sensitivities recorded in a set of color separationnegatives; providing a rigid substantially plane surfaced non-pervioussupport and mounting thereon While wet and expanded a plurality ofsheets of white opaque regenerated cellulose material of size largerthan said rigid support with marginal portions of said opaque materialoverlapping margins of said rigid support and being adhesively securedto each other and to the reverse oi said support; mounting in permanentadhe-' sion on the outer sheet of said white opaque material one of thesaid thin transparent imagebearing films in superposed adhesionalrelationship, mounting successively in image registry the remaining saidtransparent image-bearing films to complete a natural colorrepresentation, each film being in permanent adhesion to its neighborand to the opaque films comprising the refiectant base; after dryingremoving the composite photograph thus produced by peeling from itsrigid temporary support.

2. the art of color photography, a process for producing a positivetransluceny comprising multiple adhering Cellophane films which includesthe following steps; providing a rigid substantially plane polished.surface non-pervious support and covering therewith a single film ofCellophane in a condition of Wet expansion, said film bein of a sizelarger than the rigid support,- the marginal portions of said Cellophanefilm overlapping margins of said rigid support and being adheslvelysecured only to the reverse side of said rigid support by a solutioncontaining gelatine, surface moisture being removed from the face of thefilth on the front of the rigid support by squeegeeing, followed bydrying of this first or protectional film; the operation is identicallyrepeated with a second Cellophane film of plain white opaque type;adhesive similarly being placed only on the overlapping marginalportions of the film, causing it to adhere only to the back of the rigidsupport, the squeegee being again used to eliminate surplus moisture andair bubbles: drying follows; a third sheet of Cellophane of plain whiteopaque quality is prepared in similar size being placed in water toobtain maximum expansion; gelatin adhesive is applied to the entiresurface of the second film on the rigid support; the third is placed incontact, squeegeed, thus being caused to adhere; the marginaloverlapping portion of said third film is then adhesively secured to theback of the rigid support; the operation as described for the third filmis exactly repeated with a fourth Cellophane film of plain white opaquetype; simultaneously with the foregoing operations a film of plain whiteopaque Cellophane is impregnated with a solution containing potassiumferricyanide, hydrochloric acid, iron and ammonium citrate; theimpregnated sheet is dried in darkness while stretched on another rigidsupport; exposure of the impregnated white opaque film to light behindthe red sensation recording negative member of a set of color separationnegatives; production of an lron blue image results; the 'surplus toningchemical is washed oif in plain water; impregnation follows with asolution containing a bichromate, with the dual result of fixing theblue coloration andr'endering the film again sensitive to light; thefilm is again dried in the dark on a rigid support; the film is nextexposed to light behind the green sensation r'ecording member of the setof color separation negatives in proper registry with the iron blueimage already formed in thc Cellophane film, after printing, the film isimpregnated with a solution containing an acid magenta dye, whichmordants into the bichromate image formed by the printing operationbehind the green sensation recording negative; the plain white opaqueCellophane film, hearing magenta and blue images, is now washed in astrong acid solution, setting both colors; simultaneously with theseoperations another Cellophane film impregnated with a bich'rornate anddyed in the clerk is exposed to light behind the blue sensationrecording member of the set of color separation negatives; afterexposure impregnation follows with a yellow acid dye; immersion in astrong acid solution follows setting the yellow dye in the regions ofthe film in which bi'chromate image has been formed by light exposurebehind the negative and releasing unwanted yellow dye from thenon-bichromated area of the film; the Cellophane film bearing the blueplus magenta image is now permanently attached by adhesion to thebuild-up of imageless film on the rigid support; the yellowimage-bearing Cellophane film is registered to the blue-magentaimage-bearing film and allowed to remain in contact suificient time todischarge its dye content into the blue-magenta image, thus forming athree color image on a single film of plain opaque Cellophane; theyellow image bearing film is now discarded; the entire Cellophanebuild-up is dried by the application of heat and air; with a sharp knifethe films comprising the structure is discarded after the translucencyformed by the foregoing operations is peeled off the rigid support.

film printed behind the blue sensation negative I with yellow colorizer;bichromate images formed by printing in each instance acting as amordant 3. A process in color photography including the preparatorysupersltion of four imageless Cellophane films on a rigid support, asdescribed in claim 2; a fifth film of plain white opaque Cellophane isimpregnated with a solution containing a bichromate. stretched on arigid support and dyed in the dark; the film is then exposed to lightbehind the green color sensation recording member of ,a' set of colorseparation negatives and printed to form a bichromate image;impregnation follows with an acid magenta dye in aqueous solution; thefihn is then treated with a strong acid solution to set the dye bymordanting in the-bichromate image; washing follows to remove dye fromthe unexposed areas; the film is then mounted with adhesive to thesuperposed structure of -four imageless films on the rigid support;squeegeeing follows to eliminate surplus moisture and obtain smoothness;simultaneously with the foregoing operations a sixth Cellophane film hasbeen similarly bichromated, dried, exposed behind a bluesensation'recording negative, impregnated with a yellow acid dye, fixedwith acid solution, washed, and while wet' and expanded caused to adherein image registry with the magenta image hearing film on the Cellophanefilm build-up; simultaneously from the red sensation recording member ofthe set of color separation negatives a positive relief film withgelatine surface has been prepared and impregnated with an acid blueimbibition dye, brought into image registry with the yellow imagebearing film of the buildup, the blue dye imbibing thereto, forming anall-Cellophane three color translucency when dried and removed from thetemporary rigid support.

4. A process in color photography including the following steps: mixinga solution containing water 90% potassium bichromate 10%, designated asthe sensitizer solution; mixing a solution containing water 95%, an acidmagenta dye 5%, designated as the magenta colorizer; mixing a solutioncontaining water.90%', an acid yellow dye designated as the yellowcolorizer; mixing a blue sensitizer-colorizer solution, containing ironand ammonium citrate, potassium ferricyanide and hydrochloric acid;preparing multiple films of plain white opaque and plain transparentCellophane by cutting to the proper size; stretohing these while wet andexpanded, as single films, over rigid supports, and drying; preparingmultiple superposed sheets of plain white opaque Cellophane in adhesionon a temporary rigid support; providing a set of color separationnegatives recording negative part-pictures in green, blue and redsensation selective sensitivities, proper .for printing in magenta,yellow and blue, respectively; impregnating a Cellophane film with thesensitizer solution and drying in darkness; exposing the dried,sensitized film to light behind the green sensation recording member ofthe color separation negative set; similarly impregnating withsensitizing solution another Cellophane film, drying and subsequentlyexposing to light behind the blue sensation recording member of thecolor separation negative series; impregnating the two films thusprinted with colorizers, the film printed behind the green sensationnegative with magenta colorizer; the

for the acid dye content of the colorizers; simultaneously impregnatinga third Cellophane film with blue sensitizer colorizer, drying the filmin the dark and exposing to light behind the red. sensation recordingmember of the color separation negative series; all three films bearingcolors are immersed in acid baths to fix the respective colors; washingfollows to clear the highlights; the three films are successively causedto adhere to the build-up of multiple imageless Cellophane films ofplain white opaque quality, in image registry and permanent adhesion, toform a natural color translucency.

5. A process in color photography which includes the following steps;impregnating a Cellophane film with a solution containing iron andammonium citrate, hydrochloric acid and potassium ferricyanide;stretching over a rigid support; drying in darkness; exposing to lightbehind a red sensation recording negative to form a blue image;immersing in a solution containing a bichromate to fix the blue imageand further sensitize the film to the action of light; exposingto lightbehind a blue green sensation recording negative; forming by suchexposure a bichromate image capable of mordanting acid dyes;impregnating the film with a solution containing a red acid dye;immersing in an acid solution thus fixing both blue and red images andeliminating red dye from the area in which there is no mordanting imagecaused by light exposure; washing the film to further clear thehighlights, thus producing a blue and red image from two separatenegatives by light exposure on a single Cellophane film.

6. In the art of color photography, the method of producing a compositecolor photograph which comprises providing in appropriate coloration asingle plain white opaque image-bearing film representing in positiveform one color aspect of the selective sensitivities recorded in a setof color separation negatives; providing in appro- 'priate colorationmultiple transparent imagebearing films representing in positive formother color aspects of the selective sensitivities recorded in said setof color separation negatives; providing a rigid substantially planesurfaced nonpervious support and mounting thereon while wet and expandeda plurality of sheets of white opaque regenerated cellulose material ofsize larger than said rigid support with marginal portions of saidopaque material overlapping margins of said support; adhesively securingsaid films to duced by peeling from said rigid temporary supa set ofcolor separation negatives; providing at least one more transparentimage bearing film in appropriate coloration representing in positiveform the remaining selective sensitivities recorded in said set of colorseparation negatives; providing a rigid substantiall plane surfacednonpervious support and mounting thereon while wet and expanded a,plurality of sheets of white opaque regenerated cellulose material ofsize larger than said rigid support with marginal portions of saidopaque material overlapping margins of said support and being adhesivelysecured to each other and to the reverse of said support; mounting inpermanent adhesion on the outer sheet of said support consisting of saidplain white opaque material the said image-bearing plain white opaquefilm in superposed adhesional relationship; mounting successively inimage registry the said transparent image bearing films to complete anatural color representation, each film being in permanent adhesion toits neigh hot and to the opaque films comprising the refiectant base;after drying removing the composite photograph thus produced by peelingfrom its rigid temporary support.

8. In the art 01 color photography, the method of producing a compositecolor photograph which comprises providing in appropriate coloration asingle transparent image-bearing film representing in positive form theselective sensitivities recorded in the exposing of blue sensation,green sensation and red sensation light sensitive photographic materialin a single simultaneous exposure in the photographing of an object;providing a rigid substantially plane surfaced non-pervious support andmounting thereon while wet and expanded a plurality of sheets of plainwhite opaque regenerated cellulose material of size larger than saidrigid support with marginal portion of said opaque material overlappingmargins of said support and being adhesively secured to each other andto the reverse of said support; mounting in permanent adhesion on theouter sheet of said opaque material the said thin transparent multipleimage bearing film in superposed adh'esional relationship to complete anatural color representation, said film being in permanent adhesion toits neighbor, the outer sheet of the opaque films comprising therefiectant base and to all the other films comprising said reflectantbase; after drying removing the composite photograph thus produced bypeeling from its rigid temporary support.

9. In the art of color photography, the method of producing a compositecolor photograph which comprises providing in appropriate colorationmultiple image-bearing films representing in positive form the selectivesensitivities recorded in a set of color separation negatives; providinga non-image-bearing film with matte surface of regenerated cellulosictransparent material; providing a rigid substantially plane surfacednonpervious support and mounting thereon while wet and expanded aplurality of sheets of white opaque regenerated cellulose material ofsize larger than said rigid support with marginal portions of saidopaque material overlapping margins of said rigid support and beingadhesively secured to each other and to the reverse of said sup-- port;mounting in permanent adhesion on the outer film of said white opaquematerial one of the said thin image-bearing films in superposedadhesional relationship; mounting successively in image registry theremaining said imagebearing films to complete a natural colorrepresentation; mounting in superposed adhesional relationship saidmatte surface film; each film being in permanent adhesion to itsneighbor and to the opaque films comprising the reflectant base; afterdrying removing the composite matte-surface photograph thus produced bypeeling from its temporary rigid support.

10. In the art of color photography, the method of producing a multiplesubject composite color photograph which comprises providing inappropriate coloration multiple transparent imagebearlng filmsrepresenting in positive form the color aspects of multiple selectivesensitivities recorded in a set of color separation negatives; providingin appropriate coloration at least one additional image-bearing filmrepresenting another subject, drawing or lettering; providing a iigidsubstantially plane surfaced nonpervious support and mounting thereonwhile wet and expanded a plurality of sheets of white opaque regeneratedcellulose material of size larger than said rigid support with marginalportions of said opaque material overlapping margins of said rigidsupport and being adhesively secured to each other and to the reverse ofsaid support; mounting in permanent adhesion on the outer sheet of saidwhite opaque material one of the thin transparent image bearing films insuperposed adhesional relationship; mounting successively in imageregistry the remaining said trans- ;parent image-bearing films tocomplete a natural color representation of one of the subjects; mountingin superposed adhesional relationship the said transparent image bearingfilms representing the other subject, drawings or letterings, tocomplete a multiple subject composite color representation; each filmbeing in permanent adheslon to its neighbor and to the opaque filmscomprising the reflectant base; after drying removing the compositephotograph thus produced by peeling from its rigid temporary support.

11. In the art of color photography, the method of producing a compositecolor photograph which comprises providing in appropriate colorationmultiple transparent image-bearing films representing in positive formthe selective sensitivities recorded in a set of color separationnegatives; providing a permanent,'substantially plane surfaced supportconsisting of paper-cardboard; providing dry mounting tissue and heatapparatus necessary for adhesional dry-mounting operation; providing atemporary rigid substantially plane surfaced non-pervious support andmounting thereon while wet and expanded a plurality of sheets of whiteopaque regenerated cellulose material of size larger than said rigidsupport, the marginal portions of said material overlapping said rigidsupport; and being adhesively secured to each other and to the reverseof said rigid support, mounting in permanent adhesion on the outer sheetof said white opaque material one of the said thin transparentimagebearing films in superposed adhesional relationship, mountingsuccessively in image registry the remaining said transparentimage-bearing films, each film being in permanent adhesion to itsneighbor and to the opaque films comprising the reflectant base;removing the composite thus produced by peeling from its rigid temporarysupport; arranging said composite in superposed relationship to saidpermanent support with dry mounting tissue sandwiched between; applyingheat to effect adhesion by means of the dry mounting tissue thuscompleting a natural color etaoaaer opaque regenerated cellulosematerial of size composite photograph suiilciently rigid for commercialusage. a

' 12. In the art of color photography, the method of providing a dualpictured composite color photography viewable by reflected light as asingle-subject picture and by transmitted light as a double subjectpicture which comprises providing in appropriate coloration multipletransparent image-bearing films representing in positive form theselective sensitivities recorded in a set of color separation negatives,these comprising the first subject; providing in appropriate colorationmultiple transparent image-bearing films representing the color aspectsof the second subject, providing multiple films of plain white opaqueregenerated cellulose: in condition-o! wet expansion; providing a rigidsubstantially plane surfaced non-pervious support and mounting thereonwhile wet and expanded a' plurality of films of plain white opaqueregenerated'cellulose material of size larger than said rigid supportwith marginal portions of said opaque material overlapping margins ofsaid rigid supportfand being adhesively secured to each other and tofthereverse of said support; mounting in permanent adhesion to the outerfilm of said plain white opaque regenerated cellulose material one ofthe thin transparent image bearing films Ofthesecnd subject insuperposed adhesional relationship; mounting successively in imageregistry. the remaining said transparent image-beari'ngfilms of thesecond subject, to complete fullj pictorial representation of saidsecond subject; mounting in superposed adhesional relationship, on'topof said second composite subject multiple films of .white plain opaqueregenerated cellulose sufficient to obscure viewing of said secondsubject when viewed by reflected light; mounting in permanent adhesionon the outer sheet of said white opaque material one of the saidthintra'nsparent films comprising one color aspect of the first subjectin superposed relationship; mounting successively in image registry theremaining larger than said rigid support with marginal portions of saidopaque material overlapping margins of said rigid support and beingadhesively secured to each other and to the reverse .of said rigidsupport; mounting in permanent adhesion on the outer film of said plainwhite opaque material one of the said image-bearing "sheets insuperposed adhesional relationship;

mounting successively in appropriate registry the remaining saidtransparent image-bearing [films to complete the representation; eachfilm being in permanent adhesion to its neighbor and 'to. the opaquefilms comprising the refiectant base; after drying removing thecomposite photo- .graphthus formed by peeling from its rigid temporarysupport.

.14. In the art of color photography, the method of producing a mattesurface composite color photograph which comprises providing a compositecolor photograph adherent to a celluloidal base consisting of multipleemulsions diiIeren-- tially colored to represent in positive form theselectivelsensitivities recorded by adherent sufaced non-pervioussupportand mounting there- .on while wet and expanded a plurality offilms said transparent image-bearing films comprising the first subject,thus completing a naturalcolor representation of the first subjectviewable by reflected light, each of the films comprising thepictorial'representations of the'first subject and of the second subjectbeing in permanent adhesion to its neighbor and to the opaque filmscomprising the original opaque base on the temporary rigid support andthe structureoi' said plain white opaque material between the second andthe first subjects; after drying removing the double subject compositephotograph thus produced by peeling from its rigid support, thusmanufacturing a product in which only the first subject, mounted on topof the dividing plain white opaque material is visible when viewed byreflected light but that when-viewed by transmitted light shows both thefirst and second subjects superposed as a double composite photograph.

13. In the art of color photography, the method of producing a compositecolor photograph including multiple subjects which comprises providingin appropriate coloration-multipletransparent image bearing films.representin .difiering color aspects of appropriately combinablesubjects, designs, letterings and drawings as recorded in photographicnegatives proper for the rendition thereof 1 in multiple colorations;providing a rigid substantially plane surfaced =-nonpervious support andmounting thereon while wet and expanded a plurality of'films of plainwhite of plain white opaque Cellophane oi size'larger than said rigidsupport with marginal portions oi saidwhite opaque Cellophaneoverlapping margins of said support and being adhesively secured to eachother and to the reverse of said support; mounting in permanent adhesionon the outer sheet of said opaque Cellophane material the said thintransparent celluloidal base film; mounting in further superposedadhesion .the said matte surface Cellophane film; each of said filmsbeing in permanent adhesion to each other and the build-up of plainwhite opaque Cellophane films; fafter drying removing the matte surfacenatural color photograph thus support. a

15. In the art of color photography, the method of producing acompositecolor photograph which comprises providing in appropriate coloration asingle transparent image-bearing film representing in positive form theselective sensitivities recorded in the exposing of blue sensation,green sensation and red sensation light sensitive superposed homogenousemulsions in the photographing of an object; providing a,non-image-bearing film with matte surface of regenerated transparentcellulosic material; providing a rigid substantially plane surfacednonpervious support and mounting thereon while wet and expanded aplurality of sheets of plain :white opaque regenerated cellulosematerial of size larger than said rigid support with marginal portion ofsaid white opaque material overlapping margins of said support and beingadhesively secured to each other and to the reverse of said support;mounting in permanent mounting thereon while wet and expanded apinrality of films of plain white opaque regenerated cellulose materialof size larger than said rigid support with marginal portions of saidopaque material overlapping margins of said rigid support and beingadhesively secured to each other and to the reverse of the said support;mounting in permanent adhesion on the outer sheet of said white opaquematerial one of said imagebearing films in superposed adhesionalrelationship; m'ounting successively in image registry the remainingsaidimage-bearing films to complete a natural color representation; mountingin superposed adhesional relationship a matte surface non-i'mage-bearingfilm, each film being I in permanent adhesion to its neighbor and to theopaque films comprising the reflectan'tbase, after drying removing thecomposite photograph thus produced by peeling from its rigid tempo- 'ysupport.

17. In the art of color photography, the methd of producing a compositecolor photograph which comprises providing in appropriate colorationmultiple collodion image bearing films representing in positive form theselective sensitivities recorded in a set of color separation negatives;providing a matte surface imageless transparent film; providing a rigid,substantially plane-surfaced non-pervious support and mounting thereonwhile wet and expanded a plurality of sheets of white opaque regeneratedcellulose material of size larger than said rigid support with marginalportions of said opaque material overlapping margins of said rigidsupport and being adhesively secured to each other and to the reverse ofthe said support; mounting in per- -manent adhesion on the outer sheetof said opaque material one of said image-bearing collodion films insuperposed relationship; mounting successively in image registry theremaining said collodion image-bearing films to complete a natural colorrepresentation; mounting in superposed relationship said matte surfacefllm; each film being in permanent adhesion to its neighbor and to theopaque films comprising the refiectant.

base, after drying removing the composite photograph thus produced bypeeling from its temporary rigid support.

18. In the art of color photography, the method of producing a compositecolor photograph which comprises providing in appropriate coloration atleast one image-bearing film representing in positive form the selectivesensitivities recorded in exposing multiple differently selectivephotographic emulsions to an object; providing a matte surface imagelesstransparent film; providing a rigid, substantially plane surfacednonpervious support and mounting thereon while wet and expanded aplurality of sheets of white opaque regenerated cellulose material ofsize larger than said rigid support with marginal portions of saidopaque material overlapping marsecured to each other and to the reverseof the said support; mounting in permanent adhesion on the outer sheetof said opaqu material said image-bearing material providing imageregistry of component selective sensitivity recordings of the objectphotographed; mounting in superposed adhesional relationship said mattesurface film, each film being in permanent adhesion to its neighbor andto the opaque films comprising the refiectant base; after dryingremoving the composite photograph thus produced by peeling from itstemporary rigid support; attaching in permanent adhesion to apaper-cardboard permanent support by dry mounting tissue in the presenceof heat.

19. In the art of color photography, the method oi producing a compositecolor photograph which comprises providing in appropriate colorationmultiple image-bearing films representing in positive form the selectivesensitivities recorded in at least one set of color separationnegatives; providing a matte surface transparent film, providingmultiple plain white translucent films; providing a rigid substantiallyplane-surfaced non-pervious support and mounting thereon while wet andexpanded a plurality of sheets of said white translucent material oisize larger than said rigid support with marginal portions of saidtranslucent material overlapping marginal portions of said rigid supportand being adhesively secured to each other and to the reverse of saidsupport; mounting on the outer sheet of said white translucent materialone of said image-bearing films in superposed adhesional relationship;mounting successively in appropriate registry the remainingimage-bearing films of one color separation series; mounting otherremaining image-bearing films in appropriate registry; mounting saidmatte surface film in superposed adhesive relationship; each film beingin permanent adhesion to its neighbor and the opaque build-up ofindividually translucent films comprising the reflective base; afterdrying, removing the composite photograph thus formed 45 by peeling fromits rigid temporary support.

20. In the art of color photography, the method of producing a compositecolor photograph which comprises providing in appropriate colorotionmultiple image-bearing films at least one of which is of surface-imagecarbon tissue bearing type, said films representing in positive form thediffering selective sensitivities recorded in at least one set of colorseparation negatives; providing multipl plain white translucent-toopaqueCellophane films; providing a rigid substantially plane surfacednon-pervious support and mounting thereon while wet and expanded aplurality of sheets of said plain White Cellophane material; saidmaterial being of a size larger than said rigid support with marginalportions overlapping said rigid support and being adhesively secured toeach other and to the reverse of the said support; mountin on the outersheet of said white Cellophane material one of said image-bearing filmsin superposed adhesional relationship; mounting successively inappropriate registry the remaining image-bearing films, each film beingin permanent adhesion to its neighbor and to the opaque build-up offilms comprising the refiectant base; after drying removing thecomposite photograph thus produced by peeling from its rigid temporarysupport.

EDWIN BOWER HESSER.

